Squashed commit of the following:

commit e000f1ef3b7bfa8042c4a0a49e28ad06dfbe6257
Author: Steffen Müller <steffen@mllrsohn.com>
Date:   Wed Jan 15 20:13:18 2014 +0100

    added readme

commit 88146dd994f4127a79c7f089024c55dcfa65b062
Author: Steffen Müller <steffen@mllrsohn.com>
Date:   Wed Jan 15 20:11:05 2014 +0100

    added require option